The terms topic or subject can be used to describe what a sentence refers to. What are the proper terms for the "source" (the person who is speaking or writing) and "destination" (the person who is listening or reading) when referring to a particular phrase used in communication?

For example, if Ann were to tell Bob: "The sky is blue" What general term would I use to describe Ann or Bob in relation to that sentence?

If they were speaking out loud, I might call Ann the speaker, and Bob the listener. If Ann had written to Bob, I might call Ann the writer and Bob the reader. In both cases, I might also call Bob the audience. Ann could be described as using the sentence to communicate with Bob. The trouble with all of these options is their actual use:

"The source of the sentence" - implies text, not a person
"The sentence speaker" - excludes writing, sounds wrong
"The sentence writer" - excludes speaking
"The person who used the sentence" - too verbose

"The sentence destination" - a tagline for your local jail?
"The sentence listener" - an upcoming Hollywood movie?
"The sentence reader" - excludes listening
"The audience of the sentence" - could imply more than one person, too verbose